Lake Mead, Nevada
Lake Mead is the largest reservoir in the United States. It is located on the Colorado River about 30 mi (48 km) southeast of Las Vegas, Nevada, in the states of Nevada and Arizona. Formed by water impounded by the Hoover Dam, it extends 112 miles (180 km) behind the dam, holding approximately 28,500,000 acre feet (35.2 km3) of water.
The lake was named after Elwood Mead (1858–1936), who was the commissioner of the U.S. Bureau of Reclamation from 1924 to 1936 during the planning and construction of the Boulder Canyon Project that created the dam and lake. Lake Mead was established as the Boulder Dam Recreation Area in 1936, administrated by the National Park Service. It was then changed to the Lake Mead National Recreation Area in 1964, this time including Lake Mohave and the Shivwits Plateau under its jurisdiction. Both lakes and the surrounding area offer year-round recreation options. The accumulated water from Hoover Dam forced the evacuation of several communities, most notably St. Thomas, Nevada, whose last resident left the town in 1938. The ruins of St. Thomas are sometimes visible when the water level in Lake Mead drops below normal.
At lower water levels, a high-water mark or "bathtub ring" is visible in photos that show the shoreline of Lake Mead. The bathtub ring is white because of the deposition of minerals on previously submerged surfaces.